I'm a fully trained and qualified laughter yoga therapist (although I've never tried to market classes because there's already a group running in my area).
I took the qualification because I recognised how much better and happier I felt after meeting with my sister and belly laughing at life and wanted to understand why that was. There is strong scientific evidence suggesting that simply
pretending to laugh, even when you don't feel like it, stimulates endorphins and lifts mood, albeit temporarily. Your body doesn't know your laughter is not real, even if your head does. Try it out at home for yourself before you knock it! Yes, you may feel a bit daft, but it works.
The course itself was an in depth look at why it works and was very interesting, but yes, I fully understand that folks are sceptical that something as simple as pretending to laugh can raise your mood.
Yet it does.
Oh, and the 'yoga' part of the title is because laughing for a period of time helps to activate your stomach muscles. Don't believe me? Think about how much your tummy hurt after you had a genuine belly laugh with friends...